Electrical device cooling cases are known that comprise:
thermally conductive inner ferrule for surrounding the electrical device; PA1 an outer enclosure adjacent to the outside surface of the inner ferrule, and including a feed inlet and an exhaust outlet for a cooling fluid; and PA1 a passage for the cooling fluid from the inlet to the outlet. PA1 a thermally conductive inner ferrule for surrounding the electrical device; PA1 an outer enclosure adjacent to the outside surface of the inner ferrule and including a feed inlet and an exhaust outlet for a cooling fluid, the enclosure being in the form of a plurality of undulations; and PA1 a passage for the cooling fluid extending from the inlet to the outlet; the plurality of undulations cooperating with the inner ferrule to define said passage, the cooling fluid being suitable for coming into thermal contact with the inner ferrule. PA1 the undulations are created by plastic deformation of the outer enclosure; PA1 the inner ferrule is fitted inside the outer enclosure deformed in this way; and PA1 the outer enclosure is welded to the inner ferrule in leakproof manner via their ends. PA1 a base element for forming the outer enclosure is positioned in tooling having undulations on its inside faces that are complementary in shape to the undulations that are to be obtained; PA1 an element of substantially incompressible material is placed inside the outer enclosure against its inside walls; PA1 the element is compressed so as to deform the walls of the outer enclosure and obtain the undulations; PA1 the element is withdrawn; and PA1 the inner ferrule is fitted in the outer enclosure while positioned in the tooling which then has the function of holding the outer enclosure in its deformed state.
The cooling fluid then circulates through the outer enclosure passing in succession via the inlet, the passage, and the outlet.
In those known cooling cases, the outer enclosure is generally either a pipe of copper or of stainless steel wound helically around the case, or else a channel inserted in the mold for making the case, and existing in the thickness thereof.
In either case, that type of structure means that there are in fact two distinct walls between the cooling fluid and the motor that is to be cooled. The exchange of heat that takes place for the purpose of cooling the motor is therefore not optimal.
Also, in the first case, the structure requires a part to be added that is relatively complex to make since the channel defined by the pipe is closed. It is therefore necessary to make that part by molding.
In the second case, there is no add-on part, but manufacture is performed likewise by molding and is thus relatively complex.
In both cases, the cooling fluid does not come into direct contact with the inner ferrule, and given the structure of the channel formed by the pipe or by the making of the mold, the heat transfer area is relatively small, since it is solely tangential.
European patent application 0 631 365 describes a motor cooling case comprising an outer cylinder and an inner cylinder made from sheet metal plates deformed to obtain a passage for the cooling liquid between the two cylinders once the ends of the plates have been welded together. The case is a force-fit on the structure of the motor.